A phenolic resin has been widely used in the field of electric and electronic appliances such as electronic materials, semiconductor materials, semiconductor packaging materials, color LCD devices, and the like.
Accompanying with a small-sized and light-weight of electric and electronic appliances in recent years, surface mounting type semiconductor package with small and thin-sized such as BGA (Ball Grid Array), CSP (Chip Size Package) and the like is increased. In these semiconductor packages, a surface area covered by gold is markedly increased, and accomplaying with this, a surface area occupied by gold plating or gold terminal is also increasing. Therefore, it causes problems in peeling at gold plating or gold terminal, burn out due to the peeling, package crack or the like.
Required characteristics for the phenolic resin to be used in electric and electronic appliances become large such as low modulus of elastics, high heat-resistance, high strength, low hygroscopicity, high adhesiveness, etc. For the purpose of improvement in characteristics, it has been known, for example, to introduce a condensed polycyclic aromatic group such as naphthol (improvement in heat-resistance), or a method of introducing an alkylene chain into a primary chain (low hygroscopicity) and the like.
Also, when a phenolic resin is used for a semiconductor package, the phenolic resin itself has properties of hard and brittle, so that it has been generally carried out to use other materials in combination (for example, an epoxy resin or a plasticizer a plasticizer) to lower modulus of elasticity of the whole resin system whereby the material is made low stress.
A phenolic resin is also one of the materials widely been used as an adhesive for a liquid crystal display device (LCD) for electric and electronic parts or a semi-conductor package. Also, specific phenol derivatives may be sometimes used for heightening various properties of an adhesive.
For example, in a conductive adhesive, in addition to an epoxy resin as a substrate resin, a polyallylphenolic resin is formulated as a curing agent to prepare an adhesive (Japanese Unexamined Patent Publication No. Hei. 6-322350).
In a tape attached with an adhesive for TAB, in addition to a polyimide resin which is a constitutional component for an adhesive, a phenol derivatives in which a sulfur atom or an oxygen atom is introduced between phenol carbon-phenol carbon is added to obtain a tape attached with an adhesive for TAB having high adhesiveness and high insulating property (Japanese Unexamined Patent Publication No. Hei. 11-260865).
Also, in an adhesive for a substrate of a flexible printing circuit, a sulfur-containing phenol derivatives having a specific structure is formulated as an antioxidant for an acrylonitrile-butadiene rubber which is a constitutional component other than a thermosetting resin (Japanese Unexamined Patent Publication No. Hei. 7-245478).
On the other hand, accompanying with further small-sizing and light-weightening of a liquid crystal display device (LCD) or a semiconductor package, more progressed high density packaging techniques have been required. Also, as a surface layer of a material to be adhered such as an anisotropic conductive film (ACF) or a die bond film in recent years, which are objects of an adhesive to be adhered, in addition to copper, a metal material difficulty adhered such as silver, gold, gold/palladium, or silicon nitride, etc. is relatively increasing.
As mentioned above, it has been known that a whole resin system is made not brittle in combination with other plasticizer, but a phenolic resin in which the resin itself is made soft whereby it has a property of not brittle has never been known. An object of the present invention is to develop a novel phenolic resin in which the resin itself is soft, and therefore, it is not brittle (having flexibility).
Also, a surface layer of a material to be adhered such as an anisotropic conductive film (ACF) or a die bond film, which are objects of an adhesive to be adhered, is likely affected by contamination. To the surfaces of such metallic materials, there are some cases that cannot necessarily be satisfied by the conventional adhesives in the points of adhesiveness, stability and the like.
An object of the present invention is to provide a novel phenol derivatives, and another object is to provide an adhesive showing an excellent adhesive force on a surface layer coated with a metal material such as copper, silver, gold, gold/palladium, etc.